IBM Aptiva, Handbook

Page: 179 / 202

How modems work 165
Disabling Call Waiting
If you use Call Waiting, you may want to disable it while
using your modem. With Call Waiting, communications
can be interrupted when a second call is waiting to be
answered.
To disable Call Waiting, contact your telephone
company. Different telephone companies have different
procedures for disabling this feature. Also, some
telephone companies cannot disable Call Waiting. Your
telephone company business office should be able to
tell you the procedures and dialing sequence required to
disable Call Waiting.
A dialing sequence is similar to a command you type on
your computer. For example, in some areas the
following dialing sequence disables Call Waiting:
(# or *)70,,,(complete telephone number)
The dialing sequence you type on your computer might
look like this:
*70,,,5554343
. The commas (,,,) pause
the modem until the command is carried out, then the
telephone number is dialed automatically.
Call Waiting will be disabled only for the duration of
your modem’s current call and only from the calling end.
For incoming calls, you may find it helpful to change the
value of register S10 to a higher number. For more
information on S registers, see “S registers” on
page 174.
Your modem communications software determines how
your modem operates with Call Waiting. For specific
instructions, see the user’s guide or online Help that
came with the communications software.
If your computer came with fax software already
installed, the fax software documentation was included
in the box your computer came in.
How modems work
If you are having problems connecting to other
modems, or are interested in learning more about how
modems work, the information in this section can help
you. This section discusses the modem connection
process, data modems, connecting to other data
modems, fax modems, and choosing fax software
programs.
Modem connection process
For two modems to connect, they must be of the exact
same type and function. A data modem can only
connect to a data modem and a fax modem can only
connect to a fax modem. Many modern modems are
designed with both data and fax capabilities. The data
components of these data/fax modems can
communicate with data modems, and the fax
components can communicate with fax modems.
The connection process is controlled by software built
into the modem. This connection process is called a
protocol. Modems communicate by protocol and